The present invention relates generally to techniques including methods and apparatuses for manufacturing materials. More particularly, the present methods and apparatuses include a temperature control for cleaving free-standing thick films from material in bulk form, such as a silicon ingot. Such free-standing thick films are useful as a photovoltaic material such as a solar cell. But, it will be recognized that embodiments in accordance with the present invention have a wider range of applicability; it can also be applied to other types of applications such as for three-dimensional packaging of integrated semiconductor devices, photonic devices, piezoelectronic devices, flat panel displays, microelectromechanical systems (“MEMS”), nano-technology structures, sensors, actuators, integrated circuits, semiconductor substrate manufacturing, biological and biomedical devices, and the like.
From the beginning of time, human beings have relied upon the sun to derive almost all useful forms of energy. Such energy comes from petroleum, radiant, wood, and various forms of thermal energy. As merely an example, human beings have relied heavily upon petroleum sources such as coal and gas for much of their needs. Unfortunately, such petroleum sources have become depleted and have lead to other problems. As a replacement, in part, solar energy has been proposed to reduce our reliance on petroleum sources. As merely an example, solar energy can be derived from “solar cells” commonly made of silicon.
The silicon solar cell generates electrical power when exposed to solar radiation from the sun. The radiation interacts with atoms of the silicon and forms electrons and holes that migrate to p-doped and n-doped regions in the silicon body and create voltage differentials and an electric current between the doped regions. Depending upon the application, solar cells have been integrated with concentrating elements to improve efficiency. As an example, solar radiation accumulates and focuses using concentrating elements that direct such radiation to one or more portions of active photovoltaic materials. Although effective, these solar cells still have many limitations.
As merely an example, solar cells rely upon starting materials such as silicon. Such silicon is often made using either polysilicon and/or single crystal silicon materials. These materials are often difficult to manufacture. Polysilicon cells are often formed by manufacturing polysilicon plates. While these polysilicon plates may be formed in a cost effective manner, they do not exhibit the highest possible efficiency in capturing solar energy and converting the captured solar energy into usable electrical power. By contrast, single crystal silicon (c-Si) exhibits suitable properties for high grade solar cells. Such single crystal silicon is, however, expensive to manufacture and difficult to use for solar applications in an efficient and cost effective manner. In particular, techniques for manufacturing single crystal silicon substrates for incorporation into solar cells involves the separation of single crystal silicon thick films from a single crystal silicon ingot originally grown.
From the above, it is seen that improved techniques for the manufacture of free-standing thick films for integrated circuit device applications including solar cells, are desirable.